Maria has two e-mail accounts, two cell phone numbers, and two social media accounts. one set of accounts she uses just for communication with her employer and her professors. by doing this, maria is using the different media accounts to to demarcate:

front and back region

Explanation:

When we are dealing with our employer or other professional businesses we have to act different than we normal act , we bring up a different self so we put in a front region.

We have to be this person who is strict , calm , professional at all times when we are dealing with our professional team.

We change the language we speak , the pictures we post on our social network ; everything has to show moral and good ethics because we don't want to risk creating an unprofessional image to our employer or business partners .

However with friends and family we can be as casual as we want to be even the langauge we use , the photos we post on our social network , we can be our normal self without any fear hence we can be in our back region.

answer; eliminate parking problems in cities, because a car took up only half as much space as a horse and buggy;

fertile good for trade etc